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32 Threads found on edaboard.com: fr4 Dielectric Constant
fr4 is very lossy (high loss tangent), your antenna will be very inefficient with fr4.
If you are using low cost fr4 (Er~4) in frequency range 10GHz to 20GHz, Er will be all over the values on the same PCB. All the microstrip theories would not apply in this situation. For those microwave frequencies you might need to use high quality laminates (from Rogers, Taconic, etc) with low Er (between 2 and 3)
for a rectifier board, you do not normally need s parameters unless it is a directional coupler. or microwave you need to choose something like GETEK or a low loss fr4 which has a slightly lower dielectric constant. If you have no board layout software, EAGLE is free.
fr4 means different things to different manufacturers! The best thing would be to build a structure on the same material you intend to use, and measure it drift over temperature.
Er is dependent on the dielectric material used (4.3-4.5 average for fr4 based PCBs. Z0 is dependent on the topology used on a PCB design, number of layers proximity to planes etc etc. Download and play with this:
HAI ALL, I have a doubt about substrate height of the patch antenna... If we use substrate material as fr4(dielectric constant=4.4) ..and while calculating the antenna equations how can i take the "Height", if the pcb and the ground plane is separated with air gap ?? Is the substrate height is "thickness of fr4" (...)
Hello Colleague, - I found an accurate equation for Zc in the book "Antennas for all applications" by John D. Kraus: Zc= Zo/(√ε r[(W⁄t)+2) 92593 Where: Zc= Characteristic Impedance Zo = Intrinsic impedance = 377Ω ε r = dielectric constant from your material: I guess is fr4. W = widt
PCB dielectric Coefficient for fr4 is not constant by frequency so that the manufacturers give this coeffcient for certain frequency,temperature and relative humidity.Therefore the dielectric coeffcient which you used to calculate characteristic impedance for PCB traces migh not be correct. In additional to, if the operating (...)
I suggest you use GE fr4 called GETEK which has 10x lower loss tangent than most fr4. W I suspect you are using lossy fr4 and also dielectric constants is much lower at 2Ghz since rated parameter . Also dielectric constant drops 10~20% as f goes up. Return loss of thinner (...)
I am making a pcb antenna which has a resonant frequency at 13.56 mhz and which will be etched onto a fr4 substrate These 13MHz "antennas" on PCB are more or less inductors, with inductive near field coupling. They are designed/calculated like other printed regular inductors, and the dielectric constant of the PCB
Hi, I am designing a single rectangular patch antenna . the substrate is fr4 and its dielectric constant is 4.4. I have used Inset feed for the antenna. The frequency is 2.4Ghz. I obtained the following results. My resonant frequency(Rf) is 2.399Ghz return loss @ Rf is 40 db There are many ways to choose the Bandwidth . I (...)
Beware that there are many different suppliers, which are interchanged by the PCB manufacturers frequently for cost reduction. Ans all have different dielectric constant and loss tangent. So in short you can only use fr4 in case you can live with these larger variations by taking it into account during the design phase.
Given your physical length of 77.8 mm and effective dielectric constant of 3.27 (did you use fr4 with er = 4.4?), I would expect the electrical length to be in the range: electrical length = 77.8mm*sqrt(3.27) = 141 mm (above the cut-off frequency). This equals a delay of about 338 degrees at 2 GHz. It will be somewhat more because of (...)
I have manyfactured simple circular patch antenna for resonant frequency 2.45 GHz. But while testing it is showing that it is resonated at 2.48 GHz. Rest all parameters are as per specifications. I thnk problem will b in εr. i selected fr4 material and εr=4.4 for simulation. Plz help regarding this.....
Hi all, My 1 mm fr4 board warps all over the place when heated. Do u know of a cheap PCB substrate with similar dielectric constant to fr4 but is stiffer? Thanks You have to compromise either on the price or the quality. Naturally you cant expect sugar at price of salt. :D Cheers
Hello vpmedina I think that dielectric constant of a laminate is independent of its thickness. But about fr4, it's produced by various companies in the world. You can find them by googling web, then you can find dielectric constant of their laminates in the datasheets. But as a rough approximation you can (...)
hi there, i need to design a 4 element patch antenna array. i have 6inches (w) by 4inches(h) fr4 board. i need to design the array so that feed network, array and impedeance transformer all fit on the stated board can someone please 1)suggest an appropriate operating frequency for the array 2)tell me the dielectric constant, loss tangent (...)
Hybrids are available from long time using PCBs with low-loss material in top of fr4. But I believed that you are looking for multilayer PCB using ONLY low-loss and high Er materials. I never seen yet let’s say: 8 layer, 10cm x 10cm board, all layers RO3010.
Depending upon your circuit if only transmission lines are there then fr4 is good it has a dielectric constant of 4.4. RT duroid is much much better but costly. You can simulate the results with both materials and can see the difference which is better for you circuit. Hope it helps
If you're looking for a check list, here's a basic one: 1) Make sure you know the dielectric constant of the board. If you use fr4, and are really high frequency (say 4 GHz) or higher, you may need to design for losses along traces. This is because the dielectric constant of fr4 is only (...)